This study will measure the effects of short-term consumption of inulin on blood lipid concentrations, iron, magnesium, and calcium absorption, fermentation in the colon, and glucose tolerance and insulin response. Inulin is isolated from chicory and is a naturally occuring storage oligomer of the carbohydrate fructose found in many plants, such as onion, garlic, artichoke, and chicory. To determine the physiological effects of a commercially-available inulin, twelve male subjects, ages 35-50 years, will consume controlled diets containing either no inulin or 15 grams of inulin per day. Subjects will complete daily questionnaires on their subjective responses to the diet. At the end of each 3 week period, the following measurements will be completed: blood lipids, including serum cholesterol, HDL-cholesterol, LDL-cholesterol, serum triglycerides, Apo A1, and Apo B. During the third week of each 3 week period, 5 day composites of feces and urine will be collected. In these samples, calcium, magnesium and iron absorption will be measured by determining fecal and urinary losses. From the 5 day fecal collection, fecal wet weight and dry weight, fecal pH, transit time, fecal short chain fatty acids, fecal bile acids and neutral steroids, an fecal enzymes will be measured. A final fresh fecal collection will be used for measurement of bacterial flora including total anaerobes, bifidobacteria, lactobacilli, enterococci, bacteroides, clostridia and coliforms (IMVIC series). Finally, glucose tolerance tests and insulin response will be measured in during the third week of each diet.